Extended Forecast Discussion NWS Weather Prediction Center College Park MD 241 PM EDT Mon Jun 06 2022 Valid 12Z Thu Jun 09 2022 - 12Z Mon Jun 13 2022 ...Dangerous/Record heat for the Southwest Friday into the weekend... ...Overview and Model Guidance Evaluation/Preferences... Broad zonal flow will trend toward increased troughing into the Northeast and western Canada (eventually the Pac NW) as upper ridging builds into the Southwest late this week into the weekend. This will favor a cooler and wetter period for much of the East late this week into the early part of the weekend with extreme heat for portions of the Southwest, and a generally warm/hot pattern for much of the rest of the West. A frontal boundary over the Southeast and Mid-South will act as a focus for more organized rain/thunderstorms in addition to a wave of low pressure moving along the Mid-Atlantic/Northeast coast Saturday. The guidance remained in overall good agreement with a blend of the 00Z/06Z models and ensembles forming a reasonable starting point. By early next week, there were difference in how quickly troughing moves into the Northwest with no clear trend in the multi-day ensembles. The National Blend of Models was an adequate middle-ground solution overall, especially with temperatures. ...Sensible Weather/Threat Highlights... For Thu/Fri, heavy rain potential will lie over the central Plains to the Mid-South (where SPC highlights a chance for severe weather) as moisture intersects the frontal boundary over some areas that have been relatively wet the past week. The system will progress eastward then northeastward along the coast, spreading rain and some storms into the Mid-Atlantic and Northeast Fri-Sat where it has been relatively dry as of late. Temperatures will be near to below normal over much of the East due to clouds and increased rain chances, but it will be hot and dry over the Southwest. With strong ridging in place by Friday, temperatures will soar into the 100s and 110s over the lower deserts which will be 10-20 degrees above normal at what is typically near the hottest time of the year in that part of the CONUS. This will challenge daily records for many locations from I-80 southward and especially focused over southern Nevada into Arizona and southeastern California. Excessive Heat Watches are in place for parts of this region for later this week through the weekend. Low temperatures will be quite warm as well, only dipping into the 70s and 80s for many locations in the Southwest. Fracasso Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, experimental excessive rainfall outlook, winter weather outlook probabilities and heat indices are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml